Many airplanes and other aerospace vehicles contain hundreds, if not thousands of meters of lines for carrying various fluids, e.g., fuel, oil, hydraulic fluids, refrigerants, heat transfer fluids, water and the like. Many of these lines, particularly lines carrying fuel, oil and hydraulic fluids, are clustered together and require clear and permanent labeling so that one line can be distinguished from another line. Since the areas or traces in which these lines are clustered often are exposed to harsh physical and/or chemical abrasion due to service and/or leaks, the labels need to be both easy to read and durable. Moreover, ideally these labels are easy for an end user to add by printing text or graphics and are easy to apply.